Hi,
Hard to take on board but it's not your duty to please your parents or your family.
I was worried to tell my family. I worried what they would think of me, her, whether they would ostracise us and so on.
However they were ok with it. Not understanding or supportive, exactly but what they did understand was that I was happy. I made it clear that if they didn't 'agree' with it, then keep it to themselves, because we didn't want to hear it. It's not their choice to make and we could do without catty and hurtful comments.
Most of them did though. At first, my stepdad and uncle didn't really respect it, but now my stepdad - seeing how normal and happy we are - isn't fazed anymore. My uncle is still a bellend but that's ok, because everyone lets him know it

But yes what I'm trying to say, for me, it wasn't as bad as I thought it would be.
I told people I'm closest to in person first - to give them a chance to ask all the questions they wouldn't want to say in front of my girlfriend in case of offending her etc. There were some awkward ones but I just made it clear I was happy and fine with it all, and they were ok after that.